Weighing too much can damage your health, and obesity is a growing problem for both kids and adults around the world. Sleep might be one answer to the problem. A new study has found that elementary school students who slept too little were more likely to gain pounds.

    Past studies have shown a link between sleeping less and weighing more, but scientists have had a tough time determining "which came first, the chicken or the egg," says Julie C. Lumeng of the university of Michigan in Ann Arbor. In other words, it hasn't been clear whether kids who weigh too much have trouble sleeping, or whether sleeping less leads to weight gain. Both scenarios (可能出现的情况) seemed equally possible.

    To get a better idea of which causes which, Lumeng and her colleagues interviewed the parents of 785 third graders from around the United States. The parents answered questions about how well their kids slept that year. Three years later, the parents answered the same questions. By sixth grade, 18percent of kids involved in the study were obese.

    The scientists found no relationship between weight and the students' race or gender. It also didn't matter how strict their parents were, or whether they were boys or girls. Obesity struck all of these groups equally. Instead, sleep seemed to be the key factor. Over the three years of study, the children averaged a healthy 9. 5 hours of sleep a night. Some kids, however, slept a lot more or less than others.

    For the sixth graders, every hour of sleep above the 9. 5houraverage was linked to a 20 percent lower risk of being obese. Sleep appeared doubly important for the third graders. Every extra hour of sleep they got was linked to a 40 percent drop in obesity.

    People from East Asia tend to have more difficulty than those from Europe in distinguishing facial expressions — and a new report published online in Current Biology explains why.

    Rachael Jack from University of Glasgow, said that rather than scanning evenly across a face as Westerners do, Easterners fix their attention on the eyes.

    "We show that Easterners and Westerners look at different face features to read facial expressions," Jack said. "Westerners look at the eyes and the mouth in equal measure, while Easterners favor the eyes and ignore the mouth."

    According to Jack and his colleagues, the discovery shows that communication of human emotions is more complex than previously believed. As a result, facial expressions that had been considered universally recognizable cannot be used reliably to convey emotions in cross­cultural situations.

    The researchers studied cultural differences in the recognition of facial expressions by recording the facial movements of 13 Western people and 13 Eastern people while they observed pictures of expressive faces and put them into categories: happy, sad, surprised, fearful, disgusted, or angry. They compared how accurately participants read those facial expressions using their particular eye movement strategies.

    It turned out that Easterners focused much greater attention on the eyes and made significantly more errors than Westerners did. "The cultural difference in eye movements that they show is probably a reflection of cultural difference in facial expressions," Jack said. "Our data suggests that while Westerners use the whole face to convey emotions, Easterners use the eyes more and the mouth less."

    In short, the data shows that facial expressions are not universal signals of human emotions. From here on, examining how cultural factors have diversified these basic social skills will help our understanding of human emotions. Otherwise, when it comes to communicating emotions across cultures, Easterners and Westerners will find themselves lost in translation.

    You can't always predict a heavy rain or remember your umbrella. But designer Mikhail Belvacv doesn't think that forgetting to check the weather forecast before heading out should result in you getting wet.

    That's why he created Lampbrella, a lamp post with its own rain sensing umbrella.

    The designer says he came up with the idea after watching people get wet on streets in Russia. "Once, I was driving on a central Saint Petersburg street and saw the street lamps lighting up people trying to hide from the rain. I thought it would be appropriate to have a canopy(伞蓬) built into a street lamp," he said.

    The Lampbrella is a standard-looking street lamp fitted with an umbrella canopy. It has a built-in electric motor which can open or close the umbrella on demand. Sensors (传感器)then ensure that the umbrella offers pedestrians shelter whenever it starts raining.

    In addition to the rain sensor, there's also a 360 motion sensor on the fiberglass street lamp which detects whether anyone's using the Lampbrella. After three minutes of not being used the canopy is closed.

    According to the designer, the Lampbrella would move at a relatively low speed, so as not to cause harm to the pedestrians. Besides, it would be grounded to protect from possible lighting strike. Each Lampbrella would offer enough shelter for several people. Being installed at 2 meters off the ground it would only be a danger for the tallest of pedestrians.

    While there are no plans to take Lampbrella into production, Belyaev says he recently introduced his creation to one Moscow Department and insists this creation should be installed on the street where a lot of people walk but there are no canopies to provide shelter.

    Self-driving cars have been backed by the hope that they will save lives by getting involved in fewer crashes with fewer injuries and deaths than human-driven cars. But so far, most comparisons between human drivers and automated vehicles have been unfair.

    Crash statistics for human-driven cars are gathered from all sorts of driving situations, and on all types of roads. However, most of the data on self-driving cars' safety have been recorded often in good weather and on highways, where the most important tasks are staying in the car's own lane and not getting too close to the vehicle ahead. Automated cars are good at those tasks, but so are humans.

    It is true that self-driving cars don't get tired, angry, frustrated or drunk. But neither can they yet react to uncertain situations with the same skill or anticipation of an attentive human driver. Nor do they possess the foresight to avoid potential perils. They largely drive from moment to moment, rather than think ahead to possible events literally down the road.

    To a self-driving car, a bus full of people might appear quite similar to an uninhabited corn field. Indeed, deciding what action to take in an emergency is difficult for humans, but drivers have sacrificed themselves for the greater good of others. An automated system's limited understanding of the world means it will almost never evaluate (评估) a situation the same way a human would. And machines can't be programmed in advance to handle every imaginable set of events.

    Some people may argue that the promise of simply reducing the number of injuries and deaths is enough to support driverless cars. But experience from aviation (航空) shows that as new automated systems are introduced, there is often an increase in the rate of disasters.

    Therefore comparisons between humans and automated vehicles have to be performed carefully. To fairly evaluate driverless cars on how well they fulfill their promise of improved safety, it's important to ensure the data being presented actually provide a true comparison. After all, choosing to replace humans with automation has more effects than simply a one-for-one exchange.

    A society that lives by the plastic fork may very well die from it. That's how things are looking. Anyway, for a world so used to disposable(一次性的) habits, any hope for a solution(解决方案) also increasingly seems to be buried.

    Sure, there have been some hopeful ideas. Boyan Slat, the Dutch inventor developed a plan for Covering the Great Pacific Garbage Patch. Not long after it started, Slat's system experienced "material fatigue(疲劳)"-likely the result of being strained(使受到压力) by all that trash-and the task was delayed.

    All the while, the plastic increases. Its growth is very fast, according to Linda Wang, a professor of chemical engineering at Purdue University. She says, "We'll have more plastic than fish by 2050." Yet Wang, along with other researchers at Purdue, may have a solution not only to this plastic problem, but also to the growing need for clean energy.  Her team has developed a system that turns waste, a durable, lightweight material that accounts for about a quarter of all plastic waste, into a highly pure form of gasoline.

    Publishing their findings in the journal Sustainable Chemistry and Engineering, the scientists' state that instead of making plastic go away, they can break it down and reuse it, using chemistry to destroy what chemistry brought to the world when plastic was developed back in 1907.

    The process uses "supercritical" water-heated to around 450 degrees Celsius (842 degrees Fahrenheit),beyond the key point at which distinct liquid and vapor phases(气液态) exist-to boil plastic waste into an oil, the researchers explain. It takes a couple of hours for the supercritical water to complete the transformation, but the result is a kind of oil that can be used as gasoline or fuel. It can also be turned into other products.

    The researchers have only made the transformation in a laboratory setting so far, but they suggest turning the process to a commercial scale(规模) may not be far off. And considering the 300 million tons of plastic into the environment every year, that day can't come soon enough. But it will come in time.

All animals play. Runing, rolling and wrestling with each other is a way for them to have fun, of course. But it also seems to be how they communicate and strengthen bonds with each other.

When a dog comes up to another dog, front legs bowed and his tail high, his buddy knows he wants to play. But new research shows that this play behavior is surprisingly similar when horses and dogs play.

To study interspecies communication, Elisabetta Palagi and her colleagues from the University of Pisa found 20 YouTube videos of dogs and horses playing where their interactions lasted at least 30 seconds. They analyzed the videos, looking for specific pattern of play.

They found that while playing, both dogs and horses often had relaxed, open mouths-which is common playful facial expression in mammals. Some also copied each other's movements, like pretending to bite, playing with an object, or rolling on their backs on the ground. A 2,000-pound horse can play with a relatively tiny dog because the two are able to communicate their intentions.

"It's an important study because it shows how two animals who look and behave so differently can nevertheless manage to negotiate how to play in a way that's comfortable for both," Barbara Smuts, a behavioral ecologist at the University of Michigan, told National Geographic.

It's even more noteworthy given the large size difference between horses and dogs. The dog is vulnerable (易受伤的) to injury by the horse, and the horse has a deeply rooted tendency to fear animals that look like wolves."

Next up, the researchers write, is exploring the development and shaping of interspecies communication that “can be at the basis of a universal language of play".